Transcript Web Application Development with ColdFusion
ColdFusion: Just the Basics
Charlie Arehart Syste
M
anage September 2000
Who Am I?
• Founder/CTO of SysteManage – Web App Dev Training, Best Practices Consulting • Allaire Certified Instructor – Teaching Allaire’s FastTrack to ColdFusion, Advanced CF classes, under contract to Fig Leaf Software • Frequent Speaker to User Groups nationwide • Monthly contributor to CFDJ Magazine • Co-author of
CF For Dummies, Professional WAP
– Other books coming out soon
Who Are You?
• Web site developer – Looking to add more interactivity to your site • Web application developer or development manager who’s heard of ColdFusion – Wondering how it works, how easy it is to use, how scalable it is for enterprise apps
What We’ll Cover
• We’ll show: – How CF can be used to add interactivity to your site – How easy it is to use and how it works – Just the basics: not presuming any CF experience • Not a sales seminar – Definitely task oriented – Discussions of basic topics and features – Several live walkthroughs, code samples
• Introduction to ColdFusion • Prominent ColdFusion Sites • Basic Coding Demonstrations • Database Integration • When to/when not to use ColdFusion • Q&A • All in just 2 hours!
Topics
Introduction to ColdFusion
About ColdFusion
• Leading Web Application Development System – more than 430,000 CF developers worldwide • Very easy to use, yet capable of enterprise class applications – being used by organizations large and small
CF: Ready for Prime Time
• Robust – Industry leading development platform, at R4.5
• Scalable – Capable of enterprise-class applications • Secure – Integrates with OS security
Broad Database Support
• CF can communicate with virtually any database, including: – SQL Server (Microsoft and Sybase) – Oracle – DB/2 – Informix – and many more enterprise DBMS’s, as well as desktop DBMS’s such as MS Access
Broad OS/Web Server Support
• CF can run on Windows 95/98/NT/2000 – as well as Unix (Solaris, HP-UX , Linux) • Can run on all web servers: – high-performance integration on Netscape, Microsoft, Apache, and other major servers
Great Portability
• CF Applications can generally be ported from one environment to another quite easily – Can generally change databases without impact on application • If using ANSI standard SQL – Can switch Web servers without impact – Can even switch platforms without code change (Unix to-Windows/vice versa) • Almost unheard of portability!
Scalability
• ColdFusion now includes built-in clustering technologies – support for running multiple CF servers to enable high-volume transaction processing • Many significant performance features • Allaire also recently acquired Live Technologies, makers of JRUN – can now integrate CF apps and Java Servlets/Java Server Pages
Yet So Easy to Use!
• All those features are great – and should give comfort when discussing CF with those not familiar with it • But what’s better, is it’s so easy to use!
• This presentation will focus on simpler aspects of using, developing in CF
Some Prominent CF Sites
Some Prominent CF Sites
• Crayola • Hertz • Toysrus • Casio • Symantec – See “enterprise security and small business” • Tag Heuer • AT&T Wireless • Learning Tree • Autobytel • Smartmoney • Netgrocer • Moen Faucets • Cotton Incorporated • And many more
And Did You Know?
• Windows2000 Magazine • SQL Server Magazine
Basic Coding Demonstrations
The Exploding Web
• Broad web accessibility, ease of HTML development have made the web explode – nearly anyone can learn and apply HTML • Often web pages become stale for lack of changing content – someone responsible for “updating” pages, job often goes undone • CF makes it easy for pages to change on the fly!
– Perhaps based on system information, or database
A Simple Dynamic Page
• Simple example: display today’s date on web page:
Our Store
Our Store
ProductsServices
CF Tag Processing
• Notice CFOUTPUT tag on previous page – this is not an HTML tag, instead is CF tag • Called CFML, or ColdFusion Markup Language – CFML looks like HTML, but is not understood by the browser • Instead, CF tags are processed on web server first: – CF tags often used to generate HTML
Server Interprets CFML
• Page containing CFML (and HTML) stored as file with .cfm extension – web server passes file to CF Server to process
Demonstrations
• Viewing CFML source • Browsing that page to see the conversion of CFML to HTML • Observing dynamic change of date/time without page modification
Server vs Client Processing
• ColdFusion page processed on server • Can only have CFML, no other server-side processing – such as ASP, PERL, Java • But
can
send to browser any valid client side code, in addition to HTML – such as Javascript, VBScript, Java applets, Activex controls, DHTML, WML, and more
• ActiveX • COM/DCOM • CORBA • Java • JSP, Servlets • Cybercash, ICVerify • Verity SEARCH'97
Side Note: Technology Integration
• Macromedia Flash • Macromedia Generator • Macromedia Dreamweaver • NetObjects Fusion • XML • WML • SMIL
Why Dynamic Pages?
• Extending last example, data to display on site may already be in databases – May want to present database-driven catalogs – may want to prompt users for input and process result (search pages, data entry applications) – may want to query or update databases • CF makes that sort of thing very easy!
Site Updating: Old Way
• Manual maintenance – many sites maintain lists of data on web pages – changes are made manually – updates are e-mailed in to person responsible • Bottleneck – maintainer must know HTML – maintainer must make time to read and process emails – some changes fall through cracks, rarely timely
Site Updating: The CF Way
• Fully automated, database-generated approach – Database created to hold site data – Static data is moved to database (copy/paste) – ColdFusion used to read data from database and display on web page. No change to user.
– New administrator interface used to update data • or let the users enter the data themselves!
Demonstrations
• New Line Software Employee App – database-driven catalog – simple search interface – drill down capability – simple data entry interface • Source code provided at end of handout
Additional Topics
• Many more features of CF to consider as beginners: – Using variables and functions – Performing conditional processing – Form processing • Including form validation – Reusing code with CFINCLUDE – Using (and perhaps creating) custom tags – Passing data among programs
Still More Topics
• Other topics worth noting: – Using CFMAIL to generate Email – Using CF’s Application framework – Using Session, Client, Application vars – Cookie processing – Gathering other web site data (CFHTTP, WDDX)
Yet More Topics
• Still other topics worth noting: – Integrating with LDAPs – Advanced Security – COM integration – Incorporating Javascript – Lots More • For now, we’ll move on to Database Integration
Database Integration
CF Can Access Server Databases
• If database is stored on the CF server – or can be reached over network from the server • That data can be made available on the web – Can build application against it • Of course, security can be applied to limit access – No time to discuss security matters in depth • Will show how to integrate databases & CF
Some May Already Know...
• Before explaining CF database integration, let’s review basics of databases and query processing
Database Basics
• Databases are composed of tables – tables are composed of records and columns • SQL, or Structured Query Language, is a standard language for database processing – ColdFusion leverages SQL processing – you must understand SQL and db processing • but is relatively easy to learn, many resources
Tables, Rows & Columns
Database Things Places People Rows Columns 1 2 3 People Pid Name City John Jane Joe DC NY LA
Selecting Data From Table
• Most basic database processing is querying a table for data • SQL SELECT statement is simple: SELECT Name, City FROM People • Retrieves all records from PEOPLE table, returning all values for NAME and CITY columns – can list as many or as few columns as needed
Query Results
• In traditional database systems, this SQL is entered in some query tool, and the result is displayed to user: Name John Jane Joe City DC NY LA
Limiting Rows Selected
• To limit which rows are returned, use WHERE: SELECT Name FROM People WHERE City=‘DC’ • Result is: Name John
ColdFusion Query Processing
• In ColdFusion, such results are not “displayed” to user: – instead is made available to CF program as a query result set – up to CF program to determine what to show, and how to format
Side Note: DataSource Definition
• CF can work with databases defined to it – Databases are defined as “datasources” • Definition performed in the CF Administrator – Administrator is an app installed with CF Server – Generally accessible only by authorized user with administrative control over entire CF server • Datasource maps a simple name to DB’s physical location, database type, and login (if any) • Discussed in more detail in CF documentation
Executing SQL in CF
• SQL is sent to database in CF using CFQUERY:
SQL statement
• NAME attribute used for later reference
Side Note: CF Studio Query Builder
• CF Studio is the “Integrated Development Environment”, or IDE, for CF development • Primarily an advanced HTML/CFML editor, as has been demonstrated briefly • Valuable component is Query Builder – allows easy drag and drop creation of SQL – can test SQL without creating CF code to process – can build queries against all databases on server
Demonstration
• Defining a datasource • CF Query Builder – viewing data in various server database tables – using query building features against a single table • Placing SQL in a CFQUERY
Result of SQL Statement
• While most SQL processing tools simply automatically display the results – CF holds results in memory to be displayed at your control – we refer back to the query by its NAME attribute within CFOUTPUT • All column names from resulting SQL become variables: #queryname.columname#
Demonstration
• Viewing CFQUERY results
Looping Through Results
• Often a query will result in many records, all held in memory awaiting processing • CFOUTPUT QUERY=“xxx” loops through all records in query named “xxx” – can optionally indicate startrow and maxrows
statements that are looped over
Demonstration
• Looping over CFQUERY results QUERY="GetEmployees" > #strLName#, #strFName#: (#strTitle#)
Using Results to Build HTML
• Result of CFQUERY can be simply displayed, or used to format HTML elements: – Tables, Lists, Form elements – and much more
Demonstration
• Building Table From Query Results
| #strLName#, #strFName# | (#strTitle#) | #strPhone# | # strEmail# |
Dynamic SQL
• SQL within a CFQUERY can certainly refer to CF variables and functions:
Still More Dynamic SQL
• Can even use CF tags to conditionally perform SQL:
Building a Search Interface
• Can use this to build search interfaces • Form presents prompts for user to describe expected results – action page builds SQL and search criteria using form data to add criteria • See New Line Employee Mgt Search feature for demonstration and example code
Additional Topics
• Many more important database topics: – More complex SQL – Multi-table Joins – Transaction processing – Use of Stored Procedures, Triggers, Views – Caching database query results – Much More
When and When Not to Use CF
CF For Everything?
• Many do indeed use CF for all web app dev – Some find they can do everything they need – Sometimes, they’re misusing it when something else would do a better job • At low volumes, may not notice – When scalability is a concern, need to give each job to the right tool
Don’t Do the Database’s Work
• Many beginning developers, new to SQL, force CF to do work that SQL could do – Performing a query within a loop over another query is almost always a missed opportunity for a join – And rather than looping over a record set to get a count, use SQL COUNT() aggregate function – Rather than perform input conversions in CF, and then need to manage that code among several apps, do it instead in the database as trigger or stored procedure – Consider stored procedures rather than performing SQL in CFQUERY
Leverage Other Objects
• Most organizations use tools besides CF – may have incorporated business rules in them • Can leverage existing COM or Corba objects, or JavaBeans, using CFOBJECT • Can leverage existing java servlets with CFSERVLET • Can extend CF using C++ with CFX’s • Many more such examples
Server Side Java
• Java Server Pages and Java Servlets are relatively new means to perform web application development in Java – Provide many capabilities similar to CF – JSP is even coded as embedded statements within HTML – Perhaps easier to find Java developers – Sometimes more scalable in some solutions
Allaire: Major Player in Server Side Java
• Allaire acquired Live Software, makers of JRUN, a leading JSP and servlet engine – Has already led to enhanced integration between CF and java – Upcoming release of CF will embody even more substantial integration of the CF and J2EE
Learning More About CF and Java
• See Jeremy Allaire’s interview in Java Developer Journal, at: – www.sys-con.com/java/archives/0507/radio/index.html
– He clarifies how the move to java is not a threat to Cf developers, just an alternative development platform and improved underlying architecture • See also the Allaire site’s Developer area for articles on the subject
CF vs. ASP
• Frequently asked question – For beginning developers, CF is much easier to learn – When maintaining someone else’s code, it’s much easier to understand at a glance – A given CF program is much shorter than same in ASP • But sites with strong VB skills will gravitate to it • The fact that it’s free seems a false economy – Due to learning curve and increased code size – And CF is very inexpensive compared to other products
Conclusion
CF: The Developer’s Choice
• We’ve seen how easy CF is to work with • How database integration is trivial • How CF has many features to solve wide range of problems • How it can integrate with other tools when necessary
CF: A Complete Environment
• Discussed that it’s also: – scalable (clustering, caching, etc.) – secure (advanced security, integrated with OS) – robust (fail-over, load balancing, multi-threaded) – integrated with other tools and resources (CORBA, COM, Java, and more) • CF Studio provides integrated dev env (IDE)
Where to Learn More
• • ColdFusion documentation – Included with server, and with Studio
ColdFusion Web Application Construction Kit
Ben Forta, et al – THE bible in many people’s eyes , by • www.allaire.com
– an excellent informational and support web site • ColdFusion Developer’s Journal – www.coldfusionjournal.com
• FusionAuthority.com, Defusion.com, many more
Great Beginner SQL Resource
• Sams’
Teach Yourself SQL In 10 Minutes
, by Ben Forta – Great, simple, inexpensive, easy to understand introduction to SQL, especially as is typically used in environments like CF
• And enjoy ColdFusion!
• Q & A time